POLYMER SWELLING .15. SWELLING AND DESWELLING STUDIES OF POLYSTYRENE LIQUID-SYSTEMS IN BINARY-SOLUTIONS

The specific sorption capacities of poly(styrene-co-divinylbenzene) [i.e., (Sty)1-x(DVB)x samples for binary solutions of toluene (alpha = 1.98)] and a second solvent [i.e., heptane (alpha = <0.01), methanol (alpha = <0.06), acetone (alpha = 0.92) or chloroform (alpha = 3.00)] were correlated with the corresponding DVB mole fraction (x) in the sorbent polymer samples (0.01 < x < 0.11), with the volume fraction (z) of toluene in the sorbed binary liquid (which was cycled at least twice from z = 0 to z = 1 and back to z = 0 in increments of 0.1) and with the adsorption parameter (alpha) of the sorbed liquid. These correlations demonstrated that the sorption capacity during the initial transit from z = 0 to 1 reflects the molecular architecture in the original dry state. Once the samples have been swelled to saturation in toluene (z = 1), however, the ''memory'' of the former dry state is erased; thereafter the sorption capacity reflects only the architecture established in the fully swollen state, and the composition of the sorbed solution. The molecular nature of the solvent exchange processes is discussed in the text. (C) 1994 John Wiley & Sons, Inc.